I just purchased a Union Armera/Grulla model 210E 20 gauge sidelock side by side. It has H&H type 7 pin sidelocks, double triggers with articulated front trigger, splinter fore end and prince of wales grip. It has a D1 date stamp indicating 1958 manufacture which is long before Union Armera completely switched over to using Grulla as their name, the barrels are marked Union Armera and the serial number has the U.A. prefix, the water table has the Grulla stamp with the standing Crane and the word "Grulla". The butt plate has the standing crane and the words "Escopetas Grulla, U.A."
Overall it is a nicely made and good handling gun. When I bought it was I was told it was choked Modified and Full. I had intended to have the chokes opened or thin walled choke tubes installed for use on ruffed grouse. However when I look at the bore and choke markings it has nominal bore diameters of 15.6mm, with chokes of 15.3mm and 15.1mm. This would equal constrictions of 0.3mm and 0.5mm, which according to the charts I have would be equivalent to British 1/4 and 1/2 chokes, or North American Improved Cylinder and Modified chokes. Is this correct?
I know that 15.6mm is on the tight end of bores for a 20 gauge, and I have been told that tightly bored Spanish guns often shoot tighter patterns than might be predicted by the choke constriction alone. Obviously I will pattern the gun and see how it shoots with a variety of loads before I decide for sure whether the chokes need to be opened (or thin walled tubes installed). However I am interested to hear the opinions of more experienced shotgunners on this.
Overall it is a nicely made and good handling gun. When I bought it was I was told it was choked Modified and Full. I had intended to have the chokes opened or thin walled choke tubes installed for use on ruffed grouse. However when I look at the bore and choke markings it has nominal bore diameters of 15.6mm, with chokes of 15.3mm and 15.1mm. This would equal constrictions of 0.3mm and 0.5mm, which according to the charts I have would be equivalent to British 1/4 and 1/2 chokes, or North American Improved Cylinder and Modified chokes. Is this correct?
I know that 15.6mm is on the tight end of bores for a 20 gauge, and I have been told that tightly bored Spanish guns often shoot tighter patterns than might be predicted by the choke constriction alone. Obviously I will pattern the gun and see how it shoots with a variety of loads before I decide for sure whether the chokes need to be opened (or thin walled tubes installed). However I am interested to hear the opinions of more experienced shotgunners on this.
